Rotary engines use the rotation of a piston to convert pressure into a rotating motion, instead of using reciprocating pistons. In these engines, the rotor typically includes a number of seals that remain in contact with wall(s) of the rotor cavity of the engine throughout the rotational motion of the rotor to create a plurality of rotating chambers when the rotor rotates.
Rotary engines come in many forms. One well-known type, the Wankel engine, has a generally triangular rotor received in a two-lobed epitrochoid cavity. Other non-Wankel rotary engines types exist as well.
Some rotary engines include a pilot subchamber for pilot ignition, in which the tip portion of an ignition element such as a glow plug is received. However, known arrangements are not optimized and room for improvement exists.